Estrogen and progesterone receptor content of GnRH analogue pretreated and untreated uterine leiomyomata

Receptors of hypothalamic-pituitary-ovarian-axis hormone in uterine myomas

In this study the expression of GnRH, FSH, LH, ER-α, ER-β, and PR receptors was examined in uterine myomas of women in reproductive and perimenopausal age. In cases of GnRH and tropic hormones a membranous and cytoplasmic immunohistochemical reaction was detected, in cases of ER-α and PR the reaction was located in cell nucleus, and in the case of ER-β it manifested also a cytoplasmic location. In some of the examined cases the expression was detected in endometrium, myocytes, and endothelium of blood vessels, in uterine glands and myoma cells. In myometrium the level of GnRH and LH receptors increases with age, whereas the level of progesterone and both estrogen receptors decreases. In myomas of women in reproductive age, independently of their size, expression of GnRH, FSH, and LH receptors was more pronounced than in myometrium. In women of perimenopausal age, independently of myoma size, expression of LH and estrogen α receptors was higher while expression of GnRH receptors was lower than in myometrium. FSH receptor expression was not observed. Expression of estrogen receptor β was not affected by age of the woman or size of myoma. Analysis of obtained results indicates on existing in small myomas local feedback axis between GnRH-LH-progesterone.

Characterization of estrogen receptors alpha and beta in uterine leiomyoma cells

OBJECTIVE

Cellular and subcellular localization of estrogen receptor alpha (ERalpha) and estrogen receptor beta (ERbeta) in uterine leiomyomas.

DESIGN

Retrospective study.

SETTING

University of La Laguna (ULL) and Canary University Hospital (HUC).

PATIENT(S)

Premenopausal and postmenopausal women with uterine leiomyomas.

INTERVENTION(S)

Hysterectomy and myomectomy.

RESULT(S)

Estrogen receptor alpha was only present in smooth muscle cells with variation in the subcellular location in different leiomyomas. Estrogen receptor beta was widely distributed in smooth muscle, endothelial, and connective tissue cells with nuclear location in all cases studied; variations were only found in the muscle cells for this receptor.

CONCLUSION(S)

Estrogens operate in leiomyoma smooth muscle cells through different receptors, alpha and beta. However they only act through the ERbeta in endothelial and connective cells.

A comparative study of the effect of raloxifene and gosereline on uterine leiomyoma volume changes and estrogen receptor, progesterone receptor, bcl-2 and p53 expression immunohistochemically in premenopausal women

OBJECTIVE

To compare the mechanism of action of raloxifene and gosereline induced shrinkage of leiomyomas via estrogen receptor, progesterone receptor, bcl-2 and p53 expression immunohistochemically.

STUDY DESIGN

Thirty-two premenopausal women affected by uterine leiomyomas were randomized into two equal groups. Group A was treated with gosereline (3.6 mg subcutaneous injection monthly) and group B was treated with raloxifene (60 mg daily per os) for 3 months before undergoing surgery. At entry and at the end of the treatment the leiomyoma volume was measured ultrasonografically and the volume change was calculated. Immunohistochemical detection of estrogen receptor (ER), progesterone receptor (PR), bcl-2 and p53 were performed on leiomyoma tissue samples from group A, group B and the matched-control group. H-scores for ER, PR, bcl-2 and p53 were calculated. The mean volume changes of leiomyomas and immunohistochemical H-score differences of ER, PR, bcl-2 and p53 were compared between groups.

RESULTS

The leiomyoma volume decreased significantly after treatment in gosereline group from baseline of 65 cm(3) to 35 cm(3), and in raloxifene group from 68 cm(3) to 50 cm(3), p<0.05. The difference between the before and after treatment leiomyoma volumes between the two treatments was not statistically significant. H-score of ER expression was significantly lower in gosereline group compared to control group (54.4 versus 113.2, p = 0.001), whereas H-score of PR expression was significantly lower with both gosereline and raloxifene groups compared to control group (64.8 for gosereline versus 94.6 for control, 73.6 for raloxifene versus 94.6 for control, p = 0.001). The bcl-2 expression was higher in both gosereline and raloxifene groups compared to control group (173.7 for gosereline versus 94.7 for control, 179.7 for raloxifene versus 94.7 for control, p = 0.001). The p53 expression was only lower with gosereline than the control group (169.4 versus 205.6, p = 0.001), whereas there was no significant change between the raloxifene group and the control group (201.9 versus 205.6) (p>0.05).

CONCLUSION

Raloxifene was as effective as gosereline in reducing leiomyoma volumes. Decreased PR expression may be a mechanism for tumor growth reduction in raloxifene treatment. In both treatment modalities, the mechanism of shrinkage of leiomyomas could not be increased apoptosis mediated by bcl-2 and p53 expression and should be investigated by further studies.

Effects of treatment with gonadotropin releasing hormone agonist on the uterine leiomyomata structure

OBJECTIVE

Our aim was to study the effects of the gonadotropin releasing hormone agonist on the uterine leiomyoma of infertile women.

MATERIAL AND METHODS

Sixty-seven nulliparous women (aged 24-39 years) with uterine leiomyomas, underwent ultrasonographic study of leiomyoma volume, and were divided in two groups. Thirty-one had nodes greater than 300 cm3 and were treated with goserelin 3.6 mg every 28 days for 6 months (group I); the other 36 patients did not receive medication (group II or control group). Sixteen patients from group I had < or = 36% (median) reduction of the leiomyoma volume (subgroup Ia) and the other 15 women had reduction > 36% (subgroup Ib). All women underwent myomectomy.

RESULTS

The group with the greater leiomyoma reduction after treatment with goserelin (group Ib) showed a significantly lower percentage of ER+ when compared with group Ia and the control group. Group Ib had a significantly higher percentage of PR+ in relation to the control group, but not to group Ia. The number of blood vessels, AgNOR dots, and cells, and the amount of collagen were not different between the three groups studied. Leiomyomata reduction correlated negatively with the percentage ER+ cells, but positively with the PR+ cells, amount of collagen and number of blood vessels. No correlation was found between the number of AgNOR dots and cellularity.

CONCLUSION

Our data strengthen the hypothesis that the uterine leiomyoma response to steroid hormones results from the presence of specific hormone receptors, and progesterone receptors may also play a role in the development of leiomyoma.

Differential effect of gonadotropin-releasing hormone analogue treatment on estrogen levels and sulfatase activity in uterine leiomyoma and myometrium

OBJECTIVE

To investigate the effect of GnRH treatment on estrogen levels and sulfatase activity in leiomyoma and myometrium tissue.

DESIGN

Retrospective analyses of tissue obtained in a prospective randomized clinical study.

SETTING

Gynecology departments of eight hospitals in the Netherlands.

PATIENT(S)

Thirty-two patients scheduled for leiomyoma surgery.

INTERVENTION(S)

Patients were randomized to receive either GnRHa (3.75 mg/4 weeks of triptorelin or 3.6 mg/4 weeks of goserelin) or no GnRHa for 4 months. At subsequent surgery, leiomyoma and myometrium samples were collected.

MAIN OUTCOME MEASURE(S)

Estrone, estradiol, and sulfatase activity levels in leiomyoma and myometrium.

RESULT(S)

In myometrium, levels of estrone, estradiol, and sulfatase activity were significantly lower in the treated group (to median values of 46%, 21%, and 61%, respectively). In leiomyomas of treated patients, the reduction in median estrone level (to 65% of untreated value) was comparable to that in myometrium. The reduction in estradiol level in leiomyoma, however, was significantly less than in myometrium (median to 58% vs. 21%), and no significantly lower sulfatase activity was found.

CONCLUSION(S)

Estradiol and sulfatase results show that the effect of GnRHa treatment on leiomyoma differs from the effect on myometrium, suggesting a continuing estrogenic stimulus in leiomyoma tissue despite treatment.

Immortalization of human uterine leiomyoma and myometrial cell lines after induction of telomerase activity: molecular and phenotypic characteristics

In vitro model systems for studying uterine leiomyomas are limited in that human-derived leiomyoma cells grow poorly in culture compared with normal myometrial cells and begin to senesce early, at approximately passage 10 in our studies. To our knowledge, a good in vitro human-derived cell culturing system for leiomyomas does not exist. In an attempt to fill this void, we have immortalized a uterine leiomyoma cell line by inducing telomerase activity, which allows cells to bypass their normal programmed senescence. Telomerase activity was induced by infecting the target (uterine leiomyoma and normal myometrial) cells with a retroviral vector containing hTERT, the gene for the catalytic subunit of telomerase. Subsequent analysis by RT-PCR and the telomeric repeat amplification protocol assay confirmed expression of the inserted gene and induction of telomerase activity in leiomyoma and myometrial cells. Analysis of cells for estrogen receptor-alpha and progesterone receptor proteins by Western blotting showed no change in expression of these proteins between the immortalized and parental leiomyoma and myometrial cells. Both immortalized and parental myometrial and leiomyoma cells expressed the smooth muscle-specific cytoskeletal protein alpha-actin and were negative for mutant p53 protein as evidenced by immunocytochemical staining. The immortalized leiomyoma and myometrial cells showed no anchorage-independent growth, with the exception of a small subpopulation of immortalized leiomyoma cells at a higher passage that did form two to three small colonies (per 50,000 cells) in soft agar. None of the immortalized cells were tumorigenic in nude mice. In conclusion, our data show the successful insertion of the hTERT gene into leiomyoma and myometrial cells and the immortalization of these cell lines without phenotypic alteration from the parental cell types (up to 200 population doublings). These cells should help to advance research in understanding the molecular pathways involved in the conversion of a normal myometrial cell to a leiomyoma cell and the mechanisms responsible for the growth of uterine leiomyomas. Answers to these questions will undoubtedly lead to the development of more effective treatment and intervention regimens for clinical cases of uterine leiomyoma.